Magnetism in the S=1 frustrated antiferromagnet GeNi2O4 studied using implanted muons

TL;DR

This study uses muon-spin relaxation to investigate magnetic transitions in GeNi2O4, revealing complex magnetic environments and partial ordering of magnetic subsystems.

Contribution

It provides detailed insights into the magnetic phase transitions and the nature of magnetic ordering in GeNi2O4 using muon-spin relaxation techniques.

Findings

Identification of two magnetic transitions in GeNi2O4.

Observation of distinct magnetic environments below the lower transition.

Evidence of partial magnetic ordering of subsystems.

Abstract

We present the results of a muon-spin relaxation study of GeNi2O4. We provide further clarification of the two transitions to the antiferromagnetic state and measure the magnetic field dependence of the heat capacity up to 14 T. Both oscillatory and relaxing signals are observed below the lower transition (at temperature $T_{N2}) in the muon-decay positron asymmetry spectra, arising from two distinct types of magnetic environment. A possible explanation is suggested in terms of the separate ordering of two magnetic subsystems, one of which does not order fully down to the lowest measured temperature.